South Korean films and television shows have presented no-holds-barred spectacles of depraved violence and soul-shaking twists. Squid Game, which recently premiered its second season, is no exceptionand one of the series' key actors, Gong Yoo, previously starred in another gem of the South Korean genre.

In The Squid Game, Gong plays the Recruiter, the enigmatic and well-dressed agent who lures potential players by challenging them to a game of ddaki. The Recruiter's handsome face and friendly demeanor make it easy for his character to convince unsuspecting borrowers to try their luck—both at ddakji and then at the higher-stakes mystery game.

In Train to Busan, that same magnetism draws you in and makes you root for Seok Woo, a divorced workaholic trying to escape a zombie outbreak with his young daughter Su-an. By now, zombie flicks are a tried and true genre; We've seen every kind of take on zombies, from the emotionally intense The Last of Us to the parodic Shaun of the Dead. But "Train to Busan" offers much more.

What makes "Train to Busan" one of the best zombie movies ever is her relentless energy. Much like the bullet train that the characters are trapped on, once it gets going, it never lets up.

Premise: An infected woman jumps on a high-speed train full of innocent passengers who must then avoid a growing horde of zombies. From the frenetic hand-held camera shots to the fast-paced editing, we are rocket-launched into this terrifying situation from which there seems to be no escape. The scariest thing about these zombies—besides the close-ups of their twisted, gleeful grins and rotting flesh—is that they're fast and driven by a bloodthirsty instinct that's hard to overcome. Their savage violence, combined with the small, claustrophobic space of the train, creates one adrenaline-pumping sequence after another.

But amidst all this craziness, Train to Busan never loses sight of the devastation and human pain of becoming a zombie. We often see close-ups of fathers and daughters, husbands and wives, and all kinds of friends and families deeply affected by the transformations of their loved ones into these mindless creatures. "Train to Busan" has a strong emotional core, even in its most terrifying scenesleading to an incredibly moving finale. Train to Busan explores the harrowing flip side of losing control and turning into a monster, while delivering dazzling apocalyptic action. You get to see a lot more of Gong Yoo's acting in this movie, as his role as the Recruiter in The Squid Game, although crucial, is minor.